Chair back



FIG. 1 is a front perspective view of a first embodiment of a chair back showing my new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a right side elevational view thereof, a left side elevational view being a mirror image thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a front perspective view of a second embodiment of a chair back showing my new design;

FIG. 8 is a rear perspective view thereof;

FIG. 9 is a front elevational view thereof;

FIG. 10 is a rear elevational view thereof;

FIG. 11 is a right side elevational view thereof, a left side elevational view being a mirror image thereof;

FIG. 12 is a top plan view thereof;

FIG. 13 is a front elevational view of a third embodiment of a chair back showing my new design;

FIG. 14 is a rear elevational view thereof;

FIG. 15 is a right side elevational view thereof, a left side elevational view being a mirror image thereof;

FIG. 16 is a top plan view thereof;

FIG. 17 is a front perspective view of a fourth embodiment of a chair back showing my new design;

FIG. 18 is a rear perspective view thereof;

FIG. 19 is a front elevational view thereof;

FIG. 20 is a rear elevational view thereof;

FIG. 21 is a right side elevational view thereof, a left side elevational view being a mirror image thereof; and,

FIG. 22 is a top plan view thereof.

The broken lines showing is included for the purpose of illustrating environment of the design and forms no part of the claimed design. 

The ornamental design for a chair back, as shown and described. 